Welder with integrated wire feeder having single-knob control

ABSTRACT

A welding-type component is disclosed having a single user input that requires a user to input only a single parameter to identify a welding-type process. From the single input, operating parameters for the welding-type process automatically are set or otherwise determined. The invention streamlines the welding-type process prescription process by allowing a user to input only a single parameter than can be used to determine and coordinate other parameters for the welding-type process.

BACKGROUND OF THE INVENTION

The present invention relates generally to welding machines and, moreparticularly, to a welder or wire feeder having a single-knob controlknob for inputting a single identifier of a welding process from whichall operating parameters of the welding process can be automaticallydetermined. The present invention is particularly applicable withwelders having an integrated wire feeder.

MIG welding, formerly known as Gas Metal Arc Welding (GMAW), combinesthe techniques and advantages of TIG welding's inert gas shielding witha continuous, consumable wire electrode. An electrical arc is createdbetween the continuous, consumable wire electrode and a workpiece. Assuch, the consumable wire functions as the electrode in the weld circuitas well as the source of filler metal. MIG welding is a relativelysimple process that allows an operator to concentrate on arc control.MIG welding may be used to weld most commercial metals and alloysincluding steel, aluminum, and stainless steel. Moreover, the travelspeed and the deposition rates in MIG welding may be much higher thanthose typically associated with either Gas Tungsten Arc Welding (TIG) orShielded Metal Arc Welding (stick) thereby making MIG welding a moreefficient welding process. Additionally, by continuously feeding theconsumable wire to the weld, electrode changing is minimized and assuch, weld effects caused by interruptions in the welding process arereduced. The MIG welding process also produces very little or no slag,the arc and weld pool are clearly visible during welding, and post-weldclean-up is typically minimized. Another advantage of MIG welding isthat it can be done in most positions which can be an asset formanufacturing and repair work where vertical or overhead welding may berequired.

MIG systems generally have a wire feeder that is used to deliverconsumable filler material to a weld. The wire feeder is typicallyconnected to or integrated with a welder or a power source that powersthe driver motor(s) of the wire feeder as will generate a voltagepotential between the consumable filler material and the workpiece. Theterms “welder” and power source” are interchangeable as both refer to awelding system component designed to condition power. This voltagepotential is then exploited to create an arc between the filler materialand the workpiece and melt the filler material and workpiece in a weld.Generally, control parameters are input by a user using a several knobsand switches on a control panel of the power source. Additionally, thewire feeder may also include a series of knobs and switches designed toidentify parameters or operating conditions of the wire feeder. Otherknown wire feeders have been constructed such that control of the powersource can be governed based on the inputs to the wire feeder. MIGsystems have been developed wherein the wire feeder and welder arehoused within a common enclosure. Such integrated systems are generallypreferred by retail and infrequent users.

A variant of MIG welding is Flux-Cored Arc Welding (FCAW). With FCAW, aconsumable tubular electrode has its core filled with flux and alloyingagents. The sheath, or solid metal portion of the electrode, typicalaccounts for 80 to 85% of the weight of the electrode. During FCAW, thecored, consumable electrode is continuously delivered to the weld from aspool or other feed supply. The welding arc and weld puddle is typicallyshielded from the surrounding atmosphere by a shielding gas, such ascarbon dioxide. However, gas-less FCAW systems have been developed foropen-arc welding by introducing fluxing materials that provide greaterquantities of smoke for shielding purposes. This is advantageous inwindy conditions where the shielding gas would normally be blown away.One exemplary gas-less FCAW system is the Handler® 125 integrated welderand wire feeder commercially available from Hobart Welders of Troy,Ohio, a subsidiary of Illinois Tool Works Inc. of Glenview, Ill. HANDLERis a registered trademark of Illinois Tool Works Inc. Flux-cored MIGwelding is typically performed with a welder specifically configured forFCAW, such as the Handler®125 commercially available from HobartWelders; however, other welders have been developed that are capable ofFCAW and other MIG welding processes, such as the Handler® 140commercially available from Hobart Welders.

Flux-cored welding is often a preferred welding process when wirewelding in an environment where a shielding gas cloud might be blownaway. Flux-cored welding is also considered a relatively easy weldingprocess and, as a result, is often preferred by infrequent,inexperienced, and retail users. Flux-cored welding is also applicablewith a wide range of materials and wire diameters (wire thicknesses).High travel or deposition rates are also supported by FCAW which reducesweld time.

With MIG welding and its variants, such as FCAW, it is critical that auser properly identify the operating parameters of the welder (powersource) and/or wire feeder. To achieve consistent and proper operation,a user must enter identifiers or parameters of a welding process thatare consistent with one another. For example, an inexperienced user mayinput the value for a desired weld voltage that is inconsistent giventhe wire feed speed value also input by the user. That is, the voltagepotential created between the driven consumable filler and the workpieceis inversely proportional to the speed or velocity by which theconsumable filler is delivered. As such, as wire feed speed increases,weld voltage decreases. Therefore, the user may input values for weldvoltage and wire feed speed that are incongruous. In other words, thepower source may be unable to deliver a voltage at the level desired bythe user given the speed the wire feeder is delivering filler materialto the weld, and vice-versa.

Systems have been developed to simplify the prescription process of awelding session. Some of these systems use costly, heat generating,complex circuits and controls that pre-determine if the desired outputparameters can be attained given the multiple user inputs and, if not,provide an error message on an LCD or other display to the user. Whileadvantageous for the inexperienced or infrequent user, an error messagemay add to the complexity of the prescription process as the user maynot know what changes are necessary to the inputs to reach the desiredoutput. Other systems have attempted to solve this problem by reducingthe number of control knobs, selectors, and the like; however, forinexperienced or infrequent users, simply reducing the number ofcontrols can add to the complexity of the prescription process and mayadd to the confusion as the user must comprehend the interrelationshipbetween the various settings commanded by user manipulation of thecontrols. Absent this understanding, the user may have difficulty inprescribing or carrying out a welding session.

Therefore, it would be desirous to have a welding-type component whoseoperation can be repeatedly and effectively defined in only a singleuser-input. In this regard, it would be desirable to have a system thatreduces the complexity typically associated with defining a welding-typeprocess. It would be further desirable to have an FCAW welder/wirefeeder whereupon a single identification of weld material thickness isthe only input necessary to establish operating parameters of the FCAWwelder/wire feeder.

BRIEF DESCRIPTION OF THE INVENTION

The present invention solves the aforementioned drawbacks with a singleknob or equivalent device to input a single parameter or identifier of awelding-type process such that the operating parameters for thewelding-type process can be automatically determined from the singleuser-input.

A welding-type component, e.g. wire feeder, power source, and the like,is equipped to have a single input device capable of identifying asingle parameter of a welding-type process. From the single user-input,the parameters of the welding-type process are determined. In thisregard, a user need only provide a single input when establishing awelding-type process. In one exemplary embodiment, a user identifies amaterial thickness of a material to be weld during a welding process andfrom that single input, operating parameters of the wire feeder andpower source, such as weld voltage and wire feed speed, areautomatically set. Thus, the present invention is designed, in oneaspect, to simplify and streamline prescribing a welding-type process.The present invention is applicable with welding systems havingstand-alone welders and wire feeders as well as integrated welders andwire feeders. The invention is also applicable with general MIG weldingsystems as well as variants thereof, such as FCAW systems.

Therefore, in accordance with one aspect, the present invention includesa welding-type system having a control panel that includes only a singleinput device configured to allow a user to input a single identifier ofa welding-type process. The system further has operational circuitryconfigured to establish operating parameters for the welding-typeprocess from the single identifier.

In accordance with another aspect of the present invention, a controlleris configured to receive a user-input identifying a weld materialthickness and, from the user-input, determine operating parameters of awelding-type component. The controller is also configured to control thewelding-type component to deliver an output consistent with thedetermined operating parameters.

According to another aspect, the present invention includes a welderhaving a single means for establishing a welding-type process as well asmeans for determining operating parameters for the welding-type processfrom an input to the single establishing means. The welder also hasmeans for controlling the welding-type process consistent with theoperating parameters.

Various other features, objects and advantages of the present inventionwill be made apparent from the following detailed description and thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate one preferred embodiment presently contemplatedfor carrying out the invention.

In the drawings:

FIG. 1 is a schematic cross-sectional view of an integrated welder/wirefeeder applicable with the present invention.

FIG. 2 is an elevational view of an exemplary control panel of awelding-type component in accordance with one aspect of the presentinvention.

FIGS. 3A-3B is a schematic diagram illustrating an exemplary circuit forcontrolling operation of a welding system in accordance with one aspectof the present invention.

FIG. 4 is a flow chart setting forth the steps of defining and carryingout a welding process with a welding session incorporating the presentinvention.

FIG. 5 is a schematic cross-sectional view of an MIG welding systemapplicable with the present invention.

FIGS. 6A-6E is a schematic diagram illustrating an exemplary circuit forcontrolling operation of a welding system in accordance with anotheraspect of the present invention.

FIG. 7 is an elevational view of an alternate control panel of awelding-type component in accordance with another aspect of the presentinvention.

FIG. 8 is a flow chart setting forth the steps ofparameter-determination process in accordance with another aspect of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will be described with respect to an integratedwelding system wherein the welder and the wire feeder are housed withina common enclosure. However, one skilled in the art will readilyappreciate that the present invention is also applicable with a“non-integrated” system having a stand-alone welder and a stand-alonewire feeder. Furthermore, the invention will be first described withrespect an integrated welder/wire feeder designed only for FCAW.However, as will be described with respect to FIGS. 5-8, the presentinvention is also applicable with multi-process welding systems.

A cross-sectional view of an exemplary integrated welder/wire feeder isillustrated in FIG. 1. As shown, welding system 10 includes anintegrated welder/wire feeder 12 having a single housing 14 thatencloses the components of a wire feeder as well as the components of awelder. As shown, disposed with housing 14 is a spool 16 of consumablewelding wire 18. The wire may be flux-cored or self-shieldingflux-cored. The wire 18 is translated from the spool 16 to a welding gun20 by motor and drive assembly 22. The integrated welder/wire feeder 12also includes a power conditioner assembly 24 designed to condition araw power input into a form usable by the welding process. Extendingfrom the welder/wire feeder 12 via a weld cable 26 is clamp 28. Clamp 28is designed to complete the electrical circuit with the workpiece 30during the welding process. The welding gun 20 is connected to theintegrated welder/wire feeder 12 across weld cable 32. As will bedescribed in greater detail below, the integrated welder/wire feeder 12has a control panel 34 having a single-knob control 36 for a user toinput a single identifier or parameter of the welding process. Oneskilled in the art will appreciate that while preferably on front panel34, the single-control knob may be conveniently positioned on any of theside panels or the back panel. In addition to knob 36, welder/wirefeeder 12 may also have a dedicated ON/OFF switch to turn the system ONand OFF. It is also contemplated that such an ON/OFF selection may alsobe integrated into the single control knob 36.

As referenced above, welder/wire feeder 12 is an integrated systemdesigned, in one embodiment, to carry out a FCAW process wherein aflux-cored consumable wire is fed to a weld. In this regard, it iscontemplated that welder/wire feeder may operate in a gas-less mode andthus deliver a self-shielding, flux-cored consumable to the weld. Theintegrated welder/wire feeder 12 includes a control panel 34 thatpreferably has only an ON/OFF switch (not shown) and a single controlknob 36. An elevational view of the control panel 34 is shown in FIG. 2which illustrates the preferred single knob 36 and an ON/OFF switch 38.While an ON/OFF switch 38 is shown in addition to the control knob, itis contemplated that the control knob may be configured to rotate to anON/OFF position and thus eliminate the need for switch 38. Additionally,while a rotatable, variable-positional knob 36 is illustrated, it iscontemplated that other user-input devices may be used including, butnot limited to switches and push-buttons.

Referring now to FIG. 2, control panel 34 includes, in one embodiment,an ON/OFF switch 38 vertically positioned in a lower-right corner of thecontrol panel 34; although, other locales are contemplated. The ON/OFFswitch 38 is designed to receive a pushing force from a user such thatthe switch is depressed in the ON direction when it is desired to turnthe system ON and depressed in the OFF direction when it is desired toturn the system OFF. It is recognized that other devices may be used inplace of the illustrated push-button switch to selectively control thewelder/wire feeder between an ON state and an OFF state, such as amulti-position, rotatable knob and the like.

The control panel 34 also includes control knob 36 that, in theillustrated embodiment, is designed to be rotated to one of a number ofdiscretely defined positions 40. In the illustrated embodiment, each ofthe defined positions corresponds to a range of work-piece materialthicknesses or gauges. In a preferred embodiment, in addition to amultitude of material thickness positions, a “FAN ONLY” position 42 isalso provided.

Control knob 36, in the embodiment illustrated in FIG. 2, is designed tobe positioned at one of the material thickness selection positions 40 orthe fan only position 42. In this regard, control knob 36 is notdesigned to be positioned between any two positions. That is, as shownin the labels for each position 40, there is not a material thicknesssetting defined between positions 40. As such, each position 40 definesa range of material thicknesses. In the illustrated example, there is an“18-16 GA” position, a “16-12 GA” position, a “12-10 GA” position, and a“10 GA- 3/16 in.” position. One skilled in the art will readilyappreciate that the above ranges are merely exemplary and that othermaterial thicknesses are contemplated. Additionally, it is alsocontemplated that other parameters instead of or in addition to materialthickness may also be used to identify particulars of a welding process.As further shown in FIG. 2, in a preferred embodiment, control panel 34includes a legend 44 to assist a user in identifying the gauge of a weldmaterial from knowledge of its thickness, and vice-versa. In anexemplary embodiment, welder/wire feeder 12 is designed to only carryout an FCAW process. As such, each of material thickness selectionpositions 40 corresponds to a range of weld material thicknesses. Aswill be described, by only identifying the corresponding materialthickness, operating parameters for the FCAW process are set. In oneembodiment, wire feed speed is pre-set; therefore, only a weld voltageneed be determined from an input to the single-knob control 36.

As referenced above, in one embodiment, the present invention isdirected to an FCAW welder/wire feeder that requires a user to inputonly a single parameter, i.e. material thickness, to prescribe an FCAWwelding process. Accordingly, circuitry in the welder/wire feeder isdesigned to receive the single user input and from that single userinput automatically set operating parameters of the components of thewelding-type system. In the example illustrated in FIG. 2, a singleinput of material thickness is required and, from only that materialthickness selection, operating parameters of a welder/wire feeder, suchas weld voltage, are automatically set. This is particularlyadvantageous for infrequent or inexperienced users that are not aware ofthe optimal weld voltage and wire feed speed for a given wire diameterand material thickness. As such, the invention enables a user toidentify the gauge of the material to be weld by the welder/wire feederand from that characteristic, the operating parameters of thewelder/wire feeder are determined. In a preferred embodiment, no otheruser inputs are needed to prescribe the welding session than the singleinput provided with positioning of control knob 36. As will bedescribed, the operating parameters may be set by a controller definedby operational circuitry, a microprocessor, or a combination of both.That is, for purposes of this application, “controller” shall not beconsidered limited to only microcontroller or microprocessor-basedconfigurations. While the “controller” disclosed herein may include amicrocontroller or a microprocessor, neither is required. As such, thedisclosed “controller” may be comprised of non-programmable operationalcircuitry, such as a voltage divider circuit.

Referring now to FIGS. 3A-3B, a schematic diagram illustrates anexemplary circuit in accordance with one embodiment of the presentinvention. In this embodiment, operating parameters are determineddirectly within a circuit rather than with a microprocessor andassociated algorithms. One skilled in the art will appreciate that theelectronic components and the interrelation thereof illustrated in FIGS.3A-3B is but one contemplated circuit and that other circuitarrangements as well as other electronic components are contemplated.

Circuit 46 includes a transformer-rectifier power supply that includes atransformer T1 and a rectifier assembly SR1. Transformer T1 is designedto step down an input voltage to a voltage suitable for the weldingprocess. In a preferred embodiment, transformer T1 is designed to stepdown a 115 VAC input to a voltage level suitable for welding flux-coredwire. The voltage is controlled through a tapped-primary scheme in whichrange switch S2 selects the desired primary tap. Rectifier assembly SR1rectifies the secondary output of the transformer T1 to provide afull-wave rectified signal to the weld output. Inductor L1 smoothes(filters) the weld output current to provide a stable welding arc.Circuit 66 also includes a relay CR2 that is controlled by the triggerswitch of a welding gun and is used to switch the welding output ON andOFF.

Control board power is developed from a 24V secondary winding on fanmotor FM. Power switch S1 switches the input 115V to the control windingof the fan motor B1. Diodes D10, D11, D12, and D13 rectify the 24V inputto the board. Series-pass regulator, comprised of transistor Q2,resistor R8, and diode D9, clamps the rectified voltage to 29V. The 29VDC is used as the power supply for operational amplifier A1.

The weld voltage is divided by resistors R9 and R1 and presented to thebase of the series-pass transistor Q1 by non-inverting unity gainamplifier A1. The wire feed motor is driven by the scaled voltage fromR9 and R1 through Q1. The scaled voltage is thus fixed directly on thecontrol board rather than through a potentiometer or other componentthat is presented to the user for controlling wire feed speed. As such,a user need only be concerned with the voltage control S2 for thematerial thickness selection. As the weld voltage varies due to changesin the output voltage or arc length, the motor speed changes. Thisprovides a wire feed speed tracking that in concert with the fixed motorspeed reference on the control board provides a stable welding arcthroughout the specified material thickness range identified in thesingle user input by varying the output voltage only.

As referenced above, voltage control S2, which is responsive to thesingle control knob, is used to set the primary tap on transformer T1.As such, each range of material thicknesses selectable by a user throughcontrol knob 36, corresponds to a weld voltage that is achievable basedon the primary tap selected when the control knob is positioned. Thus,the wire feed speed is initially fixed directly within the circuit. Asthe output voltage changes, the wire feed speed will also vary toaccommodate the fluctuations present at the weld.

As described above, in one embodiment, the present invention is directedto a welder/wire feeder for FCAW that allows a user to simply identify aweld material thickness and from that single identifier, operatingparameters, such as weld voltage, are set. FIG. 4 illustrates the stepsof a process for carrying out welding in accordance with one embodimentof the invention. The exemplary welding process 48 begins at 50 withuser installation of consumable wire at 52. As described, the inventionis applicable to both integrated and stand-alone welding systems. Assuch, the wire may be installed into a stand-alone wire feeder or anintegrated welder/wire feeder. Additionally, for purposes ofillustration only, the wire is presumed to be a type of flux-cored wireas the welder/wire feeder is specially designed for flux-cored welding.After the wire is installed 52, the welder is preferably connected to aninput power supply 54. It is contemplated that the power supply may beprovided from a utility line as well as an engine-driven source. Afterthe welder is connected to the input power supply 54, the work lead isattached to workpiece 56 whereupon the welder/wire feeder is turned ON.It is contemplated that the welder/wire feeder may be turned ON using adedicated ON/OFF switch or rotating the single control knob from an OFFposition to an ON position or position associated with an ON state.

Once the welder/wire feeder is powered ON 58, the user then identifies amaterial thickness using the aforementioned single control knob positionon the front panel of the welder/wire feeder 60. As described above,operating parameters for the welder/wire feeder will be automaticallydetermined and/or set from the user input for identification of thethickness of the material to be weld. In one preferred embodiment, wirefeed speed is pre-set and, as a result, the only parameter to bedetermined is weld voltage. After the user has rotated the singlecontrol knob to the corresponding material thickness 60, the user maybegin the welding process by depressing the trigger or other activationdevice of the welding gun at 62. As a result thereof, the welder/wirefeeder provides the appropriate weld voltage based on theuser-identified material thickness such that welding can commence at 64.Welding will continue until the gun or torch switch is released at 66.If the user has not completed the welding session 68, 70, the processreturns to 62 and awaits user reactivation or retriggering of thewelding gun. Otherwise 68, 72, it is preferred that the user power OFFthe welder/wire feeder by switching the ON/OFF switch to an OFF positionat 74. As referenced above, the ON/OFF switch may be integrated with thematerial thickness selector control knob and, as such, the user maypower down the welder/wire feeder by rotating the control knob to an OFFposition. Thereafter, process 48 ends at 76.

Heretofore, the present invention has been described with respect to anintegrated welder/wire feeder. Moreover, the present invention has beendescribed with respect to an integrated welder/wire feeder speciallydesigned for FCAW. However, as set forth below, it is contemplated thatthe present invention may also be incorporated into stand-along weldingsystems as well as welding systems capable of carrying out other weldingprocesses in addition to, or in place of, flux-cored welding.

Referring now to FIG. 5, in accordance with another embodiment of thepresent invention, a welding-type system 78 is shown having anintegrated welder/wire feeder configured for MIG operation. The powersource/feeder 80 has a work cable 82 and clamp 84 designed to hold aworkpiece 86 and establish an electrical circuit for welding. Thewelder/wire feeder 80 also includes a welding torch or gun 94. Ashielding gas cylinder 96 is also shown connected to the wire feeder 80to provide shielding gas through hose 98 for the welding process.Furthermore, the wire feeder may be constructed to operate without gasand, thus, the present invention is also applicable with “gas-less”flux-cored wires.

The welder/wire feeder 80 includes a wire drive assembly 81 thatincludes a spool of welding wire 83 that is supplied to the weld undercontrol of a controller (not shown). The controller is governed by amicroprocessor/microcontroller capable of being programmed to operateaccording to certain algorithms and/or programs. User selections orinputs received by the controller from a display and control panel 100and an internally programmed algorithm cause welding system 78 tooperate according to a user selection. The wire feeder preferably hasonly an ON/OFF switch (not shown) and a single control knob 104 foridentifying/inputting an operating parameter to the welder/wire feeder80.

When the welding torch 94 is positioned proximate to workpiece 86,welding wire is fed into contact with the workpiece 86. Once triggered,an electrical current and voltage are generated to cause the weldingwire to be heated and melt. As a result, an electrical arc isestablished which causes the welding wire to continue to melt as well astransfer the melted welding wire to the workpiece 86 where the weldingwire fuses and cools with the workpiece 86. Because the electricalenergy supplied to the welding system is typically greater than thatrequired to melt the welding wire, most of the remaining energy is inthe form of heat which is transferred to the surface of the workpiece 86resulting in the workpiece 86 also melting and improved bonding betweenthe melted welding wire and the workpiece 86. As the welding torch 94 istranslated across the workpiece 86, melted welding wire is continuouslytransferred to the workpiece 86.

Still referring to FIG. 5, the welder/wire feeder includes a wirecompartment that has a wire type and a gas type selector 85. In thisregard, when installing the wire and connecting gas to the wire feeder,the user identifies the type of wire and gas that have been installedand connected, respectively. In combination with the weld materialthickness identified via the control knob, the microcontroller knows thegas type, wire type, and wire thickness (diameter). From thisinformation, the microcontroller then determines either from a look-uptable or on-the-fly the output or weld voltage and the appropriate wirefeed speed. In this embodiment, the wire feeder is equipped to handleseveral variations and combinations of wire type and gas type. Moreover,since the voltage reference is infinitely variable and the internalvoltage and wire feed speed controls can be controlled withpotentiometers, there is adjustability between indicated thicknesssettings that allows a user to more precisely control the weldingprocess. An exemplary circuit diagram for carrying out this alternateembodiment of the invention is illustrated in FIG. 6.

Referring now to FIGS. 6A-6E, an exemplary circuit schematicillustrating an alternate embodiment of the present invention is shown.Similarly to that heretofore described, the circuit 106 is designed toestablish operating parameters of a welding-type system based on asingle user input via a single control knob or equivalent device.Additionally, the exemplary circuit is constructed to be applicable witha welding-type system that is capable of carrying out welding with avariety of shielding gas types, consumable wire types, and wirediameters, such as that shown in FIG. 5. In this regard, when a userfirst installs the consumable wire in the wire feeder and connects ashielding gas, the user preferably sets a process identity switch 85located in the wire compartment of the wire feeder to the properposition. This is a one-time setup whenever a different wire or gas typeis to be used. Once installed, all control of the welding systemcomponents is from the single control knob 104 that is preferably on thefront panel of the wire feeder or power source. In the circuitillustrated in FIG. 6, the process identity switch is shown as a12-position rotary switch S2, but can be any number of positionsdepending on the desired number of processes for the welding-typesystem. The following table relates switch position to process type.

TABLE 1 Wire Switch Diameter Shielding Base Material/ Position (inches)Gas Wire Type 1 .024 C25 Steel/Solid 2 .030 C25 Steel/Solid 3 .035 C25Steel/Solid 4 .024 CO2 Steel/Solid 5 .030 CO2 Steel/Solid 6 .035 CO2Steel/Solid 7 .030 n/a Steel/FCAW 8 .035 n/a Steel/FCAW 9 .030 ArgonAluminum/SolidThe circuit includes a micro-controller or micro-processor U1 whichdetects the position of switch S2 and either from a look-up table oron-the-fly associates a detected switch position to a selectivewelding-type process. For example, it is contemplated that the presentinvention is applicable with a welding-type system capable of solid andflux-cored welding for various consumable wire diameters and gas types.

To conserve the number of input pins to the microprocessor U1, theprocess selector switch S2 is connected to two priority encoders U7, U8,which are logically OR'ed together by U9 to convert the twelve possibleswitch selections into a 4-bit hex number that reads on port pins,RCO-3. Table 2 sets forth the bit pattern for fifteen separate anddistinct switch positions at which the process identity knob S2 can bepositioned.

TABLE 2 Switch Position RC3 RC2 RC1 RC0 1 0 0 0 0 2 0 0 0 1 3 0 0 1 0 40 0 1 1 5 0 1 0 0 6 0 1 0 1 7 0 1 1 0 8 0 1 1 1 9 1 0 0 0 10 1 0 0 1 111 0 1 0 12 1 0 1 1 13 1 1 0 0 14 1 1 0 1 15 1 1 1 0

With 115 VAC applied to the primary winding of the fan motor FM, the fanmotor FM will turn thereby cooling the welding power source. Also, thefan motor FM has a control winding that is used to supply control powerto the welding power source. When 115 VAC is applied to the primarywinding of the fan motor FM, the control winding is rated to perform at23.6 VAC at no load and 21.9 VAC with a one-half amp load. The output ofthe fan motor control winding is full-wave rectified by diodes D12, D13,D14, and D15. The full-wave rectified signal is passed through D19 andfiltered by capacitor C21 into a smooth DC signal. In one preferredembodiment, the smooth DC signal has an amplitude of 27.0 volts DC. Thefiltered 27.0 VDC is regulated by a voltage regulator U2 to 5.0 VDC. Theoutput of the regulator is determined by the following:V _(out)=1.25V(1+R2/R1)+I _(adj) R2=1.25V(1+1000/332)+(0.0001×1000)=5.1VCapacitor C19 filters the output of the voltage regulator U2. Diode D20is also provided to protect the low impedance output of the voltageregulator U2 in the condition where the input of U20 is shorted tocircuit common. Capacitor C19 will discharge through diode D20 insteadof during the low impedance output of U2. The exemplary circuitpreferably includes an LED3 that illuminates from the presence of a 5Vpower supply.

The exemplary circuit preferably includes a zero-crossing detectioncomponent. In this regard, the signal at the anode of diode D19 is thefull-wave rectified line signal discussed above. In a preferredembodiment, this signal goes to 0V every 8.3 msec. Each time the signalat the anode of diode D19 drops below 1.4V (diode drop of D18 plusemitter-base drop of transistor Q6), transistor Q6 is switched OFF;which in turn switches transistor Q8 OFF, in removing the voltage acrossresistor R46. When the signal at the anode of diode D19 rises above 1.4Vand switches transistor Q60N, transistor Q8 is switched ON, whichapplies 5V across resistor R46. This creates a pulse which issynchronized to zero-crossings of the AC line at 120 Hz. To properly actas switches, transistors Q16 and Q8 operate in a saturation mode and, assuch, the base current drive resistors must be sized appropriately.Preferably, each current drive resistor drives 1.5 mA through a 10Kresistor in its collector circuit, resistor R47 for transistor Q6 andresistor R45 for transistor Q8. The normal gain (h_(fe)) of eachtransistor is 100, so the base drive resistor is preferably 1 M Ohm orlower. A 10K Ohm resistor is shown to apply 1.5 mA of base drivecurrent. The zero-crossing pulses are then fed into the microcontrollerU1. This allows the microcontroller to fire the SCR's Q2 and Q3 at thedesired time relative to the zero-crossing.

The exemplary circuit includes a gun switch signal circuit. When thewelding gun switch is closed, 27V is applied through RC2-16 to the basedrive resistor R31 into the base of transistor Q12. Transistor Q12 isturned OFF which turns ON transistor Q13. When transistor Q13 is turnedON, 5V is applied across resistor R64 which drives pin RB0 of themicrocontroller U1 HIGH thereby indicating a gun switch closure. Whenthe gun switch is released, RB0 is pulled LOW through resistor R64 whentransistors Q13 and Q12 turn OFF.

Circuit 106 also includes an input contactor component that when aclosure of the welding gun switch is detected, the microcontroller setsbit RB2 HIGH which turns transistor Q10 ON. This allows relays CR2 andCR3 to energize. Once the contacts of relays CR2 and CR3 closes, theinput line voltage (115 VAC) is applied to the SCR circuit and RC6. Thecontacts of relay CR2 are available so that this same control can beused for 230V operation.

The exemplary circuit also includes an over-temperature detectioncomponent. In this regard, the 27V power supply exits the circuitthrough RC2-3 and goes through power transformer T1 thermostat which isnormally closed and re-enters the circuit at RC2-9. When the thermostatcontacts are closed as in normal operation, transistor Q5 remains ONwhich pulls RB7 of the microcontroller LOW. In the event the transformerthermostat opens due to an over-temperature condition, transistor Q5will turn OFF and allow resistor R19 to pull RB7 HIGH. Whenever themicrocontroller senses that RB7 is HIGH, the gun switch signal isignored. When an over-temperature condition is present, themicrocontroller will drive RB6 HIGH which turns ON transistor Q9 therebylighting an over-temperature LED D1.

The exemplary circuit also includes a gun trigger lead protectioncomponent. Since the gun switch circuit extends into the welding torch,there is potential risk of torch damage. One such failure mode mightcause the gun switch circuit to be shorted to the weld output at thepower source. The power supply gun switch circuit is protected againstthe short to the weld output by blocking diode D16 and PTC2. The holdingcurrent of the PTC is 200 mA. If one or both of the gun switch leads areshorted at the weld output, the PTC will have current in excess of 200mA through it and it will switch to a high impedance. This effectivelyopens the circuit resulting in the removal of the gun switch signal. ThePTC will remain in its high impedance state until power is removed fromthe circuit by switching the power switch off thereby allowing the PTCto cool. Once the PTC cools, it will return to its normal low impedancestate until it sees another over-current condition. One skilled in theart will appreciate that a number of different Positive ThermalCoefficient (PTC) components or similar thermal control components maybe implemented.

Circuit 106 also includes an arc voltage control component. In thisregard, the front panel metal thickness control S2 is used to establisha reference for arc voltage control. The voltage reference is set by thevoltage divider network of resistors R59, R60, R61, R62, and the 50 kOhm front panel potentiometer. The reference signal is read by an A/Dport in A4 of the microcontroller U1. The microcontroller U1 comparesits value against a look-up table specified by the process controlswitch S2 and adjusts the digital potentiometer U6 that is connected toA1-10 to provide a proper error signal reference at A1-10. The outputvoltage of the power source is fed into pins RC3-3 and RC3-4 of themicrocontroller. The output voltage is scaled down by a factor of 10 byvoltage divider circuit, resistors R10, R52, and R7. The scaled voltageis fed into a differential amplifier circuit A1 across pins 12, 13, and14. The output of A1-14 (Vout/10) is fed into pin 6 of the differentialamplifier circuit of A1. The scaled voltage feedback is subtracted fromthe error signal reference by the differential amplifier circuitwhereupon the error signal is supplied to the A/D input RA1 of themicrocontroller. The value of the error signal is used by themicrocontroller based on a look-up table to determine the amount of timeto wait within the 8.3 msec time duration of one-half of the input lineperiod before providing a firing pulse to the SCR by driving RB5 of themicrocontroller HIGH. When RB5 goes HIGH, transistor Q7 is turned ONwhich lights the LED and the opto-coupler U3 which turns on an internaltriac. When the opto-coupler U3 turns ON, a gate current is supplied toeither transistors Q2 or Q3 depending upon a polarity of the AC inputline. Diodes D5 and D6 provide current to the proper SCR gate throughresistor R9 and an opto-coupler thereby allowing one SCR to be switchedon at a time. This closed loop system regulates to the desired voltageas referenced by the front panel control and the look-up table.Preferably, a gain of the error loop is set to a sufficiently low valueas to provide sufficient droop in the output volt/amp characteristic ofthe power source to maintain a stable arc.

The exemplary circuit further includes a feed motor control component.The wire feed motor is powered directly from the arc voltage whichenters the circuit at RC-3 and RC3-4. PTC1 provides over-currentprotection to the motor circuit. The holding current of the PTC is ratedat 1.85 amps. The normal operating current of the motor while feedingwire is preferably 0.9 amps. If the motor is stalled due to a feedproblem, the motor will draw excess current and cause the PTC to switchto a high impedance state thereby effectively opening the motor circuit.The rated trip current of the PTC is preferably 3.7 amps. The PTC willremain in its high impedance state until power is removed from thecircuit and the PTC is allowed to cool. When the gun switch is closed toinitiate the arc relay, CR1 energizes which provides a current paththrough transistor Q5, diode D7, and the motor winding. The voltagesupply for the motor is determined by a series-pass regulator transistorQ1. The regulator voltage is set by the output of the operationalamplifier A2. The voltage output of operational amplifier A2 iscontrolled by the adjustment of the digital potentiometer U4. Thedigital potentiometer sets a reference voltage at the operationalamplifier A2. This reference is fed from the Vout/10 signal applied byoperational amplifier A1. Therefore, as the arc voltage changes, thewire feed speed reference tracks the change to produce a wire feed speedtracking function. The value of the digital potentiometer is set by themicrocontroller by reading the front panel material thickness referenceand comparing the value to that stored in a look-up table or determinedon-the-fly.

To enable the potentiometer to utilize the wire feed speed trackingfeature and stay at a desired value, the exemplary circuit includes ananalog switch that is employed to switch a fixed reference through thepotentiometer so that it can be read with the fixed reference applied.After the setting is verified with the fixed reference, the fixedreference gates are opened and the gates that connect to thepotentiometer to the Vout/10 reference are closed. The circuit alsoincludes a 51V zener transient voltage suppressor D6 that is connectedacross the collector-emitter junction to clip high transient voltagespikes to protect transistor Q5. When the gun switch is released to stopthe arc, relay CR1 de-energizes. The normally-closed contacts of relayCR1 short out the motor winding which creates a dynamic braking effect.As a result, the motor stops virtually instantaneously. One skilled inthe art will appreciate that resistors R1 and R2 provide a dischargepath for the output capacitor of the power source.

The exemplary circuit also includes components for short circuitdetection. Specifically, when the microcontroller determines that thearc voltage drops below and remains at a value below a known thresholdfor sustained arc, the microcontroller determines that the gun tip hasbeen shorted to the workpiece and ignores the ON switch circuit. The gunswitch circuit will not be recognized until the trigger has beenreleased and the fault has been cleared, either as the tip is brokenfree or pulled from the workpiece.

FIGS. 6A-6E illustrates one of a number of circuit configurations thatmay be designed to carry out this embodiment of the present invention.That is, one skilled in the art will appreciate that the componentsillustrated as well as the interrelationship therebetween in circuit 106is exemplary and that other components, as well as other configurationsare contemplated and considered within the scope of the invention.

Referring now to FIG. 7, an alternate control panel 108 in accordancewith an alternate embodiment of the present invention is shown. In thecontrol panel illustrated in FIG. 7, in contrast to the control panelillustrated in FIG. 2, each position to which control knob 110 may berotated defines a specific weld material thickness. Whereas eachposition to which control knob 36 of FIG. 2 could be rotated fell withina range of material thicknesses, control knob 110, illustrated in FIG.7, may be rotated to one of a number of discrete material thicknesspositions. Additionally, it is contemplated that control knob 110 may berotated to a position that does not specifically align with a known(marked) material thickness. In this regard, the user is allowedflexibility in identifying the material thickness setting. Thisflexibility allows an experienced user to tailor control of the wirefeeder and other components of the welding system to fit particulars ofthe desired welding process. That is, while a user may be carrying out awelding process with a twenty gauge wire, positioning the control knobto be slightly misaligned with the position corresponding to “twentygauge” wire may cause the wire feeder and/or power source to deliver awire at a desired wire feed speed and weld voltage, respectively, thatis more desirable for the user than that delivered if the control knobwas precisely aligned with the “twenty gauge” marker. One skilled in theart will appreciate that the identified material thicknesses are merelyexemplary and that other material thicknesses are contemplated.

A process illustrating the processing steps carried out by amicrocontroller-based embodiment of the present invention is illustratedin FIG. 8. In this embodiment, software, firmware, and hardware areintegrally used to establish operating parameters of a welding processbased on a single user-input. As illustrated, process 112 begins atSTART 114 with powering-up of the welding system. Powering-up of thesystem is preferably achieved through user selection of a dedicatedON/OFF switch, but may also be integrated with the single control knob.Thereafter, the microcontroller receives a user input 116 identifying asingle parameter of the impending welding process. In a preferredembodiment, the single parameter is selected from a selector switch thatis labeled with the wire type, gas type, and wire thickness of the wirethat will be delivered to a weld during a welding process. The positionof the process identity switch causes the controller to obtain a knownset of predetermined welding parameters from a look-up table in memory.These parameters will be used to alter the weld voltage and wire feedspeed settings per the adjustment of the single front panel controlwhich is set to a material thickness setting.

Once the process identity is determined, the controller checks thethermostat status 118. If the thermostat contacts are open 120, 122, thecontroller switches the input contactors off and the motor input relayoff 122. If the thermostat contacts are closed 118, 124, the controllerawaits a gun switch closure 126. During this wait stage, the controlleralso monitors the process identity input device, e.g. control knob, forchanges to the process identity input. In this regard, a user can changethe identified parameter; however, as will be described, changes willnot be permitted during welding.

Once welding is initiated, e.g. user activation of a gun trigger 126,128, the welding process begins at 130, 132 by switching the inputcontactors ON 134 and the motor contactor ON 136. As will be described,steps 134-136 will not be repeated in subsequent loops 137. Process 112continues by reading the material thickness control on the front panel138. This control can be altered or “tweaked” by a user at any timeduring the welding process to fine tune the arc. A voltage control errorsignal is read in 140 and the firing of the SCRs adjusted accordingly tomaintain the desired output voltage per the material thickness settingon the front panel control. The internal wire feed speed controlpotentiometer (preferably digital) is adjusted by the controller at 142to obtain the desired wire feed speed per the material thickness settingon the front panel.

The output voltage (weld voltage) is monitored at 144 to assure that ashort-circuit condition is not present at the torch tip. This isdetermined by comparing the sensed output voltage against a low voltagethreshold. If the voltage remains below the threshold for apredetermined period of time, it can be determined that the gun tip isshorted to the workpiece. If a short-circuit condition is detected 144,146, the input contactors and motor contactor are switched OFF 148. Thesystem controller then awaits a release of the gun trigger 150 beforeproceeding. If the gun trigger has not been released 150, 152, theprocess loops back to step 148. In this regard, the process does notreturn to step 116 until the gun trigger is released 150, 154. Theoperator is expected to clear the shorted condition at this point. If noshort-circuit condition exists in 144, 156, the controller loops back tocheck the thermostat and repeat the loop. This process will continue aslong as the gun trigger remains closed 126. If the gun trigger is notclosed 126, 158, the process proceeds to step 122 and the contactors areturned OFF 122.

The present invention advantageously eliminates user confusion inprescribing a welding session by presenting the system's output controlrelative to material thickness of the material to be welded. In thisregard, the user selects the material thickness using the control knobor similar input device rather than adjusting output voltage and wirefeed speed. Additionally, the present invention reduces the coststypically associated with wire feeders having synergic control systemsthat utilizes dual-mode and triple-mode controls and input devices.Furthermore, the present invention does not require any userprogramming.

Therefore, the present invention includes a welding-type system having acontrol panel that includes only a single input device configured toallow a user to input a single identifier of a welding-type process. Thesystem further has operational circuitry configured to establishoperating parameters for the welding-type process from the singleidentifier.

A controller is also presented and configured to receive a user-inputidentifying a consumable wire diameter and, from the user-input,determine operating parameters of a welding-type component. Thecontroller is also configured to control the welding-type component todeliver an output consistent with the determined operating parameters.

The present invention also includes a welder having a single means forestablishing a welding-type process as well as means for determiningoperating parameters for the welding-type process from an input to thesingle establishing means. The welder also has means for controlling thewelding-type process consonant with the operating parameters.

As stated above, the present invention is also applicable with FCAW andMIG welding systems. The invention is also applicable with TIG and stickwelding systems. As one skilled in the art will fully appreciate, theheretofore description of welding-type devices not only includeswelders, but also includes any system that requires high power outputs,such as heating and cutting systems. Therefore, the present invention isequivalently applicable with any device requiring high power output,including welders, plasma cutters, induction heaters, aircraft groundpower units, and the like. Reference to welding power, welding-typepower, or welders generally, includes welding, cutting, heating power,or ground power for aircraft. Description of a welding apparatusillustrates just one embodiment in which the present invention may beimplemented. The present invention is equivalently applicable with manyhigh power systems, such as cutting and induction heating systems,aircraft ground power systems or any similar systems.

The present invention has been described in terms of the preferredembodiment, and it is recognized that equivalents, alternatives, andmodifications, aside from those expressly stated, are possible andwithin the scope of the appending claims.

What is claimed is:
 1. A welding-type system comprising: a control panel having only a single input device configured to allow a user to input a single identifier to select a welding-type process from a number of different welding-type processes; and non-programmable operational hardware circuitry configured to establish operating parameters for the welding-type process from the single identifier.
 2. The welding-type system of claim 1 wherein the single input device is embodied in a single control selector.
 3. The welding-type system of claim 2 wherein the single control selector is a single control knob rotatably positionable to one of a plurality of positions.
 4. The welding-type system of claim 3 wherein each position corresponds to a discrete material thickness to be welded.
 5. The welding-type system of claim 3 wherein each position corresponds to a range of material thicknesses to be welded.
 6. The welding-type system of claim 1 wherein the operating parameters established are at least one of a weld voltage and a wire feed speed of the welding-type system.
 7. The welding-type system of claim 1 configured for at least one of MIG welding and FCAW.
 8. The welding-type system of claim 1 having a wire feeder configured to deliver filler material to a weld, wherein the wire feeder speed is proportional to a weld voltage set by the non-programmable operational hardware circuitry.
 9. The welding-type system of claim 8 wherein the filler material includes one of solid wire and flux-cored wire.
 10. The welding-type system of claim 1 wherein the control panel further comprises an ON/OFF switch in addition to the single input device.
 11. A controller configured to: receive a user-input identifying a material thickness to be welded; from the user-input, determine operating parameters of a welding-type component; and control the welding-type component to deliver an output consistent with the determined operating parameters, wherein the controller comprises only non-programmable hardware circuitry to set operating parameters of the welding-type component.
 12. The controller of claim 11 further configured to automatically determine all operating parameters of the welding-type component from the user-input.
 13. The controller of claim 11 further configured to receive the user-input from a variable-positionable control knob on a control panel of the welding-type component.
 14. The controller of claim 13 further configured to determine the material thickness to be welded from a discrete position of the variable positionable control knob.
 15. The controller of claim 14 further configured to automatically determine a weld voltage and wire feed speed from the user-input.
 16. The controller of claim 15 wherein the wire feed speed is proportional to the weld voltage.
 17. A welder comprising: a single means for receiving a user-input identifying a value for a single operating parameter of a welding-type process; means for determining at least one other operating parameter for the welding-type process from the user-input to the single receiving means; and means for controlling the welding-type process consistent with the operating parameters, wherein the means for controlling comprises only non-programmable hardware circuitry.
 18. The welder of claim 17 integrated with a wire feeder, wherein the wire feeder speed is proportional to a weld voltage of the welder.
 19. The welder of claim 18 wherein the single receiving means is a multi-positional knob rotatable to one of a number of input positions.
 20. The welder of claim 19 wherein each input position identifies a material thickness to be welded.
 21. The welder of claim 19 wherein each input position identifies a range of material thicknesses to be welded.
 22. The welder of claim 18 further comprising means for determining a wire feed speed and a weld voltage from a position of the control knob, wherein the control knob position corresponds to a material thickness to be welded. 